Rotary lawnmowers have been marketed for many decades and are used almost exclusively by homeowners. Rotary lawnmowers are also used in large scale commercial applications as well. Throughout the years, many changes and improvements have been made to the rotary mowers themselves. For example, more efficient engines have been designed, electric start and other convenience features have been added, and a number of self-propelled models are available. Although numerous advances have been made to the design of the mower itself, the blade has not basically changed from the original design of a flat, rectangular steel blade sharpened on the forward leading edge. The blades must be removed from the mower to be properly sharpened, a procedure which requires tools and may result in the blade becoming unbalanced. Eventually, after repeated sharpenings, the blade must be replaced.
There have been numerous attempts to improve the original blade design by providing removable cutting edges, reversible cutters and disposable cutters. None of these designs have ever become commercially successful primarily because they are expensive and in many instances more difficult to install than the standard blade. In addition, some of these designs, in an effort to add convenience and reduce cost, have resulted in designs that are potentially dangerous. Therefore, the present commercially available original equipment blade and all replacement blades are basically the same blade design that has been used for many, many years. There is therefore a need for an improved design of a blade for rotary mowers that will make it easier for the user, especially the ordinary homeowner, to always have a sharp blade on the rotary mower. There is a further need for improved designs that will more effectively pick up cut grass and other debris and more efficiently discharge it from the mower, especially where the clippings and other debris are being bagged.
There is a further need for a blade design which will minimize damage to the blade and engine when solid objects are struck by the blade.